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[nrf toup] [Crypto] Use single-part API for PSA AEAD functions. #609

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[nrf toup] [Crypto] Use single-part API for PSA AEAD functions. #609

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99 changes: 32 additions & 67 deletions src/crypto/CHIPCryptoPALPSA.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,7 @@
#include <lib/support/BufferWriter.h>
#include <lib/support/BytesToHex.h>
#include <lib/support/CHIPArgParser.hpp>
#include <lib/support/CHIPMem.h>
#include <lib/support/CodeUtils.h>
#include <lib/support/SafeInt.h>
#include <lib/support/SafePointerCast.h>
Expand Down Expand Up @@ -71,45 +72,28 @@ CHIP_ERROR AES_CCM_encrypt(const uint8_t * plaintext, size_t plaintext_length, c

const psa_algorithm_t algorithm = PSA_ALG_AEAD_WITH_SHORTENED_TAG(PSA_ALG_CCM, tag_length);
psa_status_t status = PSA_SUCCESS;
psa_aead_operation_t operation = PSA_AEAD_OPERATION_INIT;
size_t out_length;
size_t tag_out_length;
size_t ciphertext_length = 0;

status = psa_aead_encrypt_setup(&operation, key.As<psa_key_id_t>(), algorithm);
VerifyOrReturnError(status == PSA_SUCCESS, CHIP_ERROR_INTERNAL);
// The PSA single-part API appends the tag to the ciphertext output buffer.
// So we need to allocate a temporary buffer to hold ciphertext + tag, then split them.
size_t total_output_size = plaintext_length + tag_length;
uint8_t * temp_output = static_cast<uint8_t *>(chip::Platform::MemoryAlloc(total_output_size));
VerifyOrReturnError(temp_output != nullptr, CHIP_ERROR_NO_MEMORY);

status = psa_aead_set_lengths(&operation, aad_length, plaintext_length);
VerifyOrReturnError(status == PSA_SUCCESS, CHIP_ERROR_INTERNAL);
status = psa_aead_encrypt(key.As<psa_key_id_t>(), algorithm, nonce, nonce_length, aad, aad_length, plaintext, plaintext_length,
temp_output, total_output_size, &ciphertext_length);

status = psa_aead_set_nonce(&operation, nonce, nonce_length);
VerifyOrReturnError(status == PSA_SUCCESS, CHIP_ERROR_INTERNAL);

if (aad_length != 0)
{
status = psa_aead_update_ad(&operation, aad, aad_length);
VerifyOrReturnError(status == PSA_SUCCESS, CHIP_ERROR_INTERNAL);
}
else
if (status == PSA_SUCCESS && ciphertext_length == total_output_size)
{
ChipLogDetail(Crypto, "AES_CCM_encrypt: Using aad == null path");
}

if (plaintext_length != 0)
{
status = psa_aead_update(&operation, plaintext, plaintext_length, ciphertext,
PSA_AEAD_UPDATE_OUTPUT_SIZE(PSA_KEY_TYPE_AES, algorithm, plaintext_length), &out_length);
VerifyOrReturnError(status == PSA_SUCCESS, CHIP_ERROR_INTERNAL);

ciphertext += out_length;

status = psa_aead_finish(&operation, ciphertext, PSA_AEAD_FINISH_OUTPUT_SIZE(PSA_KEY_TYPE_AES, algorithm), &out_length, tag,
tag_length, &tag_out_length);
}
else
{
status = psa_aead_finish(&operation, nullptr, 0, &out_length, tag, tag_length, &tag_out_length);
// Copy ciphertext and tag to their respective output buffers
if (plaintext_length > 0)
{
memcpy(ciphertext, temp_output, plaintext_length);
}
memcpy(tag, temp_output + plaintext_length, tag_length);
}
VerifyOrReturnError(status == PSA_SUCCESS && tag_length == tag_out_length, CHIP_ERROR_INTERNAL);
chip::Platform::MemoryFree(temp_output);
VerifyOrReturnError(status == PSA_SUCCESS && ciphertext_length == total_output_size, CHIP_ERROR_INTERNAL);

return CHIP_NO_ERROR;
}
Expand All @@ -125,45 +109,26 @@ CHIP_ERROR AES_CCM_decrypt(const uint8_t * ciphertext, size_t ciphertext_length,

const psa_algorithm_t algorithm = PSA_ALG_AEAD_WITH_SHORTENED_TAG(PSA_ALG_CCM, tag_length);
psa_status_t status = PSA_SUCCESS;
psa_aead_operation_t operation = PSA_AEAD_OPERATION_INIT;
size_t outLength;

status = psa_aead_decrypt_setup(&operation, key.As<psa_key_id_t>(), algorithm);
VerifyOrReturnError(status == PSA_SUCCESS, CHIP_ERROR_INTERNAL);

status = psa_aead_set_lengths(&operation, aad_length, ciphertext_length);
VerifyOrReturnError(status == PSA_SUCCESS, CHIP_ERROR_INTERNAL);
size_t plaintext_length = 0;

status = psa_aead_set_nonce(&operation, nonce, nonce_length);
VerifyOrReturnError(status == PSA_SUCCESS, CHIP_ERROR_INTERNAL);
// The PSA single-part API expects the tag to be appended to the ciphertext input buffer.
// So we need to allocate a temporary buffer to hold ciphertext + tag.
size_t total_input_size = ciphertext_length + tag_length;
uint8_t * temp_input = static_cast<uint8_t *>(chip::Platform::MemoryAlloc(total_input_size));
VerifyOrReturnError(temp_input != nullptr, CHIP_ERROR_NO_MEMORY);

if (aad_length != 0)
{
status = psa_aead_update_ad(&operation, aad, aad_length);
VerifyOrReturnError(status == PSA_SUCCESS, CHIP_ERROR_INTERNAL);
}
else
if (ciphertext_length > 0)
{
ChipLogDetail(Crypto, "AES_CCM_decrypt: Using aad == null path");
memcpy(temp_input, ciphertext, ciphertext_length);
}
memcpy(temp_input + ciphertext_length, tag, tag_length);

if (ciphertext_length != 0)
{
status = psa_aead_update(&operation, ciphertext, ciphertext_length, plaintext,
PSA_AEAD_UPDATE_OUTPUT_SIZE(PSA_KEY_TYPE_AES, algorithm, ciphertext_length), &outLength);
VerifyOrReturnError(status == PSA_SUCCESS, CHIP_ERROR_INTERNAL);

plaintext += outLength;
status = psa_aead_decrypt(key.As<psa_key_id_t>(), algorithm, nonce, nonce_length, aad, aad_length, temp_input, total_input_size,
plaintext, ciphertext_length, &plaintext_length);

status = psa_aead_verify(&operation, plaintext, PSA_AEAD_VERIFY_OUTPUT_SIZE(PSA_KEY_TYPE_AES, algorithm), &outLength, tag,
tag_length);
}
else
{
status = psa_aead_verify(&operation, nullptr, 0, &outLength, tag, tag_length);
}

VerifyOrReturnError(status == PSA_SUCCESS, CHIP_ERROR_INTERNAL);
chip::Platform::MemoryFree(temp_input);
VerifyOrReturnError(status == PSA_SUCCESS && plaintext_length == ciphertext_length,
(status == PSA_ERROR_INVALID_SIGNATURE) ? CHIP_ERROR_INVALID_SIGNATURE : CHIP_ERROR_INTERNAL);

return CHIP_NO_ERROR;
}
Expand Down
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